You are in: eMedicine Specialties > Pediatrics: Surgery > Urology Genital AnomaliesArticle Last Updated: Oct 24, 2008AUTHOR AND EDITOR INFORMATIONAuthor: Luigi Avolio, MD, Consulting Staff, Department of Pediatric Surgery, IRCCS Policlinico San Matteo at Pavia, Italy Luigi Avolio is a member of the following medical societies: American Academy of Pediatrics Editors: Martin David Bomalaski, MD, FAAP, Pediatric Urologist, Alpine Urology; Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine; Harry P Koo, MD, Chairman of Urology Division and Director of Pediatric Urology, Virginia Commonwealth University; Professor of Surgery, VCU School of Medicine, Medical College of Virginia; Director of Urology, Children's Hospital of Richmond; Daniel Rauch, MD, FAAP, Director, Pediatric Hospitalist Program, Associate Professor, Department of Pediatrics, New York University School of Medicine; Marc Cendron, MD, Associate Professor of Surgery, Harvard School of Medicine; Consulting Staff, Department of Urological Surgery, Children's Hospital Boston Author and Editor Disclosure Synonyms and related keywords: genital anomalies, abnormalities of the male and female external genitalia, penile agenesis, aphallia, penile duplication, diphallia, microphallus, micropenis, penile torsion, lateral penile curvature, penile deviation, penoscrotal transposition, webbed penis, buried penis, hidden penis, agenesis of the scrotum, congenital absence of the scrotum, ectopic scrotum, accessory scrotum, accessory perineal scrotum, splenogonadal fusion, labial adhesion, ectopic labium, ectopic labium majus, clitoral duplication, clitoral hypertrophy, interlabial masses, urethral prolapse, prolapsed ectopic ureterocele, hydrocolpos, hydrometrocolpos, sarcoma botryoides, rhabdomyosarcoma, periurethral cyst, persistent urogenital sinus, persistent cloaca, Kallmann syndrome, Prader-Willi syndrome, polycystic kidneys, dysplastic kidneys, horseshoe kidney, ectopic pelvic kidney, obstructive uropathy INTRODUCTIONDisorders of the external genitalia are especially troubling for parents because of the unconscious emotional significance of these reproductive structures and, probably, the consequent impact of deformities on future generations. Approximately 50 years ago, researchers demonstrated that castrated rabbit embryos of both sexes developed as females, thus proving that testes are required for development of the male phenotype in mammals. Differentiation of the primitive gonad into testis is controlled by a multitude of genes, beginning with the sex-determining region on the Y chromosome (SRY), which is believed to represent the testis-determining factor. Until 8 weeks' gestation, the human fetus is undifferentiated sexually and contains both male (wolffian) and female (müllerian) genital ducts. Wolffian structures differentiate into the vas deferens, epididymis, and seminal vesicles. Müllerian ducts develop into the fallopian tubes, uterus, and upper one third of the vagina. In the male fetus, the genital tubercle enlarges to form the penis; the genital folds become the shaft of the penis; and the labioscrotal folds fuse to form the scrotum. Differentiation occurs during 12-16 weeks of gestation and is the result of testicular hormones acting on the undifferentiated genitalia in the following ways:
In the female fetus, without the influence of the AMH, the müllerian ducts complete their differentiation, whereas the wolffian structures involute. In the absence of testosterone and dihydrotestosterone, the genital tubercle develops into the clitoris, and the labioscrotal folds do not fuse, leaving labia minora and majora. ANOMALIES IN MALESPenile agenesis Congenital absence of the penis, or aphallia, is a rare anomaly caused by developmental failure of the genital tubercle. Approximate incidence is 1 case per 30 million population. The phallus is completely absent, including the corpora cavernosa and corpus spongiosum; however, some children have been reported to have small portions of corpora cavernosa. Usually, the scrotum is normal and the testes are maldescended. The urethra opens at any point of the perineal midline from over the pubis to, most frequently, the anus or anterior wall of the rectum. More than 50% of patients with penile agenesis have associated genitourinary anomalies, the most common of which is cryptorchidism; renal agenesis and dysplasia also occur. GI defects, such as caudal axis anomalies, have also been described. Reports indicate that aphallia may be associated with pregnancy complicated by poorly controlled maternal diabetes. Infants with penile agenesis historically have undergone gender reassignment surgery, including bilateral orchiectomy with preservation of the scrotal skin for later vaginal reconstruction, labial construction, and urethral transposition. However, questions remain regarding in utero gender imprinting and the long-term psychological effects of gender conversion; increasing controversy surrounds the timing, role, and the necessity of gender reassignment. The long-accepted notion regarding the presence of a phallus or phenotypic phallic growth potential should not be the major criterion in recommending gender reassignment. Penile duplication Duplication of the penis, or diphallia, is another rare anomaly resulting from incomplete fusion of the genital tubercle. Two distinct forms of penile duplication are recognized. The most common form is associated with bladder-exstrophy complex. The patient exhibits a bifid penis, which consists of 2 separated corpora cavernosa that are associated with 2 independent hemiglands. The second form, or true diphallia, is an extremely rare congenital condition. It presents in many ways, ranging from duplication of the glans alone to duplication of the entire lower genitourinary tract. The urethral opening can be in normal position or in a hypospadiac or epispadiac position. Associated anomalies of the GI, genitourinary, and musculoskeletal systems are expected. Because these anomalies are the principal causes of mortality, examining and treating patients for these conditions as soon as possible is important. Microphallus The term microphallus, or micropenis, is applicable only to a normally formed yet abnormally short penis. Specifically, the term applies to a penis with a stretched length more than 2.5 standard deviations (SD) less than the mean for age. This condition may be considered a minor form of ambiguous genitalia with correlated medical and psychological problems similar to those of the major intersex form. The scrotum is usually normal, but testes are often small and undescended. In a few cases, the corpora cavernosa are severely hypoplastic. Measurement (ie, stretched penile length) is very important in differentiation of the various types of pseudomicropenis, particularly the buried penis in the obese infant and the penis concealed by an abnormal skin attachment. Micropenis results from a multiplicity of endocrine and nonendocrine conditions. The most common etiologies include hypogonadotropic hypogonadism, hypergonadotropic hypogonadism, and idiopathic micropenis.
Because micropenis is the result of numerous pathological conditions, assignment of sex of rearing generally is deferred until a physician determines whether the penis can grow in response to testosterone administration. In individuals with microphallus who are insensitive to the androgen, castration and gender conversion can be considered. However, in most patients with micropenis, male gender assessment can be maintained with androgen stimulation. Clinical management of this form of micropenis has been contentious, with disagreement regarding the capacity of testosterone treatment to induce a functionally adequate adult penis; moreover, no general consensus regarding dosage, method of administration, timing, and duration of androgen treatment is available. The most common therapeutic regimen includes testosterone enanthate at a dose of 25-50 mg intramuscularly once a month for 3 months. Some physicians also use testosterone cream, but its absorption varies and is not easily controllable. Debate also surrounds the timing of androgen stimulation. Research indicates that testosterone therapy in infancy and childhood augments penile size into the normal range for age in boys with micropenis secondary to fetal testosterone deficiency.1 Replacement therapy at the age of puberty results in an adult-size penis (ie, within 2 SD of the mean). Furthermore, results of this study do not support the notion, which is derived from research on rats, that testosterone treatment in infancy or childhood impairs penile growth in adolescence and compromises adult penile length. Penile torsion Verneuil first described penile torsion in 1857. In the past, physicians did not recommend operative correction because they believed that attempts to move the skin would not correct spiral alignment of the corpora cavernosa. The embryologic abnormality is often an isolated skin and dartos defect that can be remedied simply by freeing the penile shaft of its investing tissue. The rotation is usually to the left in a counterclockwise fashion. The urethral meatus is placed in an oblique position, and the median raphe makes a spiral curve from the base of the penis to the meatus. However, in some cases, penile torsion is associated with mild forms of hypospadias or hooded prepuce. Frequently, torsion is corrected by reflection of the skin and dartos tunic only. In some cases, resection of the Buck fascia provides correction. Careful alignment of the skin during closure gives an excellent cosmetic result, even when the torsion is not corrected by reflection of the penile investments. The ease of achieving a normal appearance seems to justify surgical correction. Lateral penile curvature Congenital penile curvature secondary to asymmetry of corpora cavernosa length is an uncommon penile deformity. Hemihypertrophy of a corpus cavernosum and its accompanying thickened tunica albuginea, with or without contralateral concomitant hypoplasia (rudimentary corpus), are responsible for the lateral deviation in congenital curvature of the penis. Rarely, penile deviation is accompanied by penile torsion. The anomaly can be associated with trauma, but often the patient does not have a history of corporal injury. Although the deformity generally is not severe enough to preclude sexual intercourse, it can be a source of great concern to the patient and may cause him to avoid sexual contact. The Nesbit procedure is a simple effective surgical technique to correct lateral or ventral curvature. Penoscrotal transposition Complete penoscrotal transposition is an uncommon condition in which the scrotum is located in a cephalad position with respect to the penis. A less severe form is a bifid scrotum, in which the 2 halves of the scrotum meet above the penis. It is a heterogeneous anomaly, and detection warrants careful clinical evaluation to rule out other major and life-threatening anomalies, especially of the urinary system, GI tract, upper limbs, craniofacial region, and CNS. Major renal anomalies include complete agenesis of the urinary system, unilateral or bilateral renal agenesis, polycystic or dysplastic kidneys, horseshoe kidney, ectopic pelvic kidney, and obstructive uropathy. Genital abnormalities include a disproportionately long flaccid penis, complete urethral atresia, and hypospadias. Although most reported cases are sporadic, some suggest a genetic basis for normal penoscrotal relationship. The embryological sequence responsible for this defect remains unclear. Abnormal positioning of the genital tubercle in relation to the scrotal swellings during the critical period at 4-5 weeks' gestation may affect the inferomedial migration and fusion of the scrotal swellings. If the phallic tubercle is also intrinsically abnormal, development of the corporal bodies and the urethral groove and folds may be affected; this explains the frequent occurrence of the other genital abnormalities. Surgical correction is recommended for physiological and psychological reasons. When associated with severe hypospadias, penoscrotal transposition may involve a staged surgical repair. Scrotoplasty is completed with an inverted omega skin incision that is made around the scrotal skin and the base of the penis, bringing the scrotal flaps beneath the penis. Webbed and buried penis Webbed penis is a common congenital abnormality in which a web or fold of scrotal skin obscures the penoscrotal angle. If the physician performing circumcision does not recognize the condition, the penis may become buried in a tentlike fold of skin. Recircumcision to remove the excess skin makes the situation worse by drawing hair-bearing scrotal skin onto the penis. In hidden penis, the penile shaft is buried below the surface of the prepubic skin. This happens in children with obesity because the prepubic fat is very abundant and hides the penis. The condition may also derive from poor anchorage of penile skin to deep fascia or be acquired when the shaft of the penis is entrapped in scarred prepubic skin following an extreme circumcision or other trauma. The literature describes numerous techniques for correction.2 Usually, treatment is based on resection of adherent bands and deep anchorage of the shaft at the basis of the penis. Some also advocate excision of redundant skin, multiple z-plasties, liposuction, or preputial island pedicle flap. Others advocate watchful waiting, with emphasis on weight loss and yearly follow-up. Ruling out micropenis in this situation is important. Agenesis of the scrotum Other than penoscrotal transposition, the scrotum is generally resistant to embryological abnormalities; therefore, congenital malformations are unusual. Congenital absence of the scrotum is an extremely rare anomaly, and only 4 cases (including a personal observation) have been reported in the literature.3 Upon examination, the scrotum was not present, the skin between the base of penis and the anus was completely flat without rugosa, and both testes were retained in the tubercle area lateral to the base of the penis. Reports indicate only minor associated abnormalities, including slight bilateral clinodactyly in both fourth toes and bilateral nystagmus. Chromosomal and hormonal anomalies were not reported. The idea of constructing the scrotum with a pedicle flap from the perineal skin was discarded. In view of the subsequent development of the neoscrotum, the preputial skin was used in both cases because it is richer than other tissues in androgen receptors. The procedures were uneventful, and the results were functionally and cosmetically satisfactory. Ectopic and accessory scrotum Ectopic scrotum is a rare anomaly that includes an anomalously positioned hemiscrotum. Usually, the ectopic scrotum is found near the external inguinal ring but may assume several forms. Accessory scrotum is a small empty pouch of scrotal tissue attached to the scrotum or the perineum. One review identified 16 reported cases of a suprainguinal ectopic scrotum, 4 cases of a femoral ectopic scrotum, and 19 cases of accessory perineal scrotum.4 The testis generally accompanies the hemiscrotum to its abnormal position and may be normal or dysplastic. These congenital lesions of the scrotum can occur as an isolated anomaly but are often accompanied by abnormalities of the upper urinary tract. Accessory perineal scrotum has also been observed in association with anorectal malformation. The gubernaculum is a prerequisite for the ultimate location of both the testis and scrotum, and its role is complicated by subsequent differential growth of the labioscrotal folds in which the gubernaculum is stabilized. If this interaction is disturbed, the result may be suprainguinal ectopia, penoscrotal transposition, or perineal scrotum. Although the etiology of these malformations is probably multifactorial, the existence of an inbred strain of rats that are characterized by a high incidence of ectopic scrotum suggests a genetic component to this anomaly. Treatment should attempt to bring down the scrotum and the testis. If the gonad is dysplastic and the ectopic scrotum is rudimentary, consider removal of one or both structures. Splenogonadal fusion Splenogonadal fusion is a congenital anomaly that affects both sexes, with a male-to-female ratio of 16:1. In males, the left testicle or other derivatives of the mesonephros connect to splenic tissue, usually an accessory spleen. In the female, a similar fusion occurs between the left ovary and splenic tissue. The connection may be continuous (56%) or discontinuous (44%). In the continuous type, the spleen is connected to the gonad by a strand of tissue. Patients often exhibit limb defects, micrognathia, or other congenital malformations, such as anal atresia, microgastria, spina bifida, craniosynostosis, thoracopagus, diaphragmatic hernia, hypoplastic lung, and abnormal lung fissures. The discontinuous type is not usually associated with congenital defects, and the fused gonad has no connection with the native spleen. Reports total approximately 140 cases, mostly in the urology and pathology literature.5, 6, 7, 8 This is because diagnosis typically occurs during orchiopexy or herniorrhaphy, or on autopsy. In many cases, the accessory spleen that is attached to the testicle may be misinterpreted as a primary malignant testicular tumor or an adenomatoid tumor. Knowledge of this distinction is important if the testis is to be preserved at surgery, although a rare case of simultaneous splenogonadal fusion and mixed malignant tumor of the testis has been reported.9 If splenogonadal fusion is suspected preoperatively, technetium-99m radiocolloid spleen scintigraphy can establish the correct diagnosis and permit testicular salvage. Simple excision of the splenic nodule is sufficient in all cases of discontinuous fusion. In continuous splenogonadal fusion, exploratory laparotomy is usually required to clarify the anatomy. Patient education ANOMALIES IN FEMALESLabial adhesion Labial adhesion is an anomaly frequently encountered in young girls; generally, it results from chronic inflammation of the vulva. This condition must be distinguished from labial fusion, a different lesion attributed to virilization of the female external genitalia. Labial adhesion usually is asymptomatic, but, when the introitus is completely sealed, vaginal micturition with consequent dribbling can occur; moreover, urinary stasis can predispose the child to infection. A single case of hydroureteronephrosis has been reported as an extreme and unusual complication that resolved after incision of the adherent labia. Treatment consists of topical application of 1% estrogen cream (tid for 2 wk), which is usually ineffective but does facilitate subsequent manual lysis. This procedure may be performed in an office setting with a probe or with gentle action of a finger. When the lesions are dense, the patient may require sedation. Topical application of estrogen or antibiotic cream after the procedure is important to avoid recurrence of the adhesion. Ectopic labium and clitoral duplication Ectopic labium majus is a rare anomaly and is homologous to ectopic scrotum in the male. It has been reported with renal agenesis or dysplasia and the vertebral defects, anal atresia, tracheoesophageal fistula, esophageal atresia (VATER) association. Clitoral duplication is usually seen in bladder exstrophy/epispadias complex in girls. Clitoral hypertrophy Hypertrophy of the clitoris is observed in cases of fetal exposure to androgens. The disorder is usually the result of congenital deficiencies of the adrenal enzymes of cortisol synthesis; more rarely, it is caused by idiopathic virilization or exposure to progestational agents in utero. Although rare, clitoral hypertrophy caused by neurofibromas of the clitoral corpora has been described, including a case of localized neurofibromatous infiltration of the prepuce only. Treatment is dictated by the degree of masculinization, specifically by the degree of clitoral hypertrophy and, if relevant, the level at which the vagina enters the urogenital sinus. Reduction clitoroplasty with resection of the corpora according to the Spence-Allen technique gives better results than the technique described by Pelleren. Furthermore, the Pelleren plication technique often is complicated by painful engorgement of the recessed corpora at puberty. Interlabial masses Identification of an interlabial mass in a young girl may cause much concern in parents and physicians because of confusion about its etiology, implications, and treatment. However, knowledge of the most frequent anomalies responsible for interlabial mass may allow a prompt and correct diagnosis.
Persistent urogenital sinus and cloaca Congenital malformation involving the urogenital sinus and cloaca remains one of the most severe birth defects compatible with life. Moreover, management of this malformation is one of the greatest challenges of pediatric surgery and urology. Development of the lower urinary tract and genital and anorectal systems is correlated closely in females. Consequently, abnormal embryological development can involve all 3 systems. Despite the long tradition of embryological studies, the mechanisms of development of many congenital malformations are still debated. In very young embryos, the hindgut is a simple structure that, cranially, is in continuity with the midgut and, caudally, is in contact with the ectoderm, thus forming the cloacal membrane. As development progresses, the caudal part of the hindgut or cloaca separates into 2 distinct organ systems, the urogenital tract and the anorectal tract. This separation may be the result of a subdivision of the cloaca by a septum, the so-called urorectal septum. However, the nature of this septum and its mechanism of development are controversial. Kluth and Lambrecht demonstrated that the hindgut enters the cloaca from the dorsocranial direction, whereas the allantois (ie, the forerunner of the bladder) can be individuated as a cranioventral diverticulum.10 The urorectal folds can be observed between this diverticulum and the hindgut, marking the cranial border of the undifferentiated hindgut or cloaca. The importance of the septation process has likely been overestimated, and normal development of the hindgut probably depends primarily on normal formation of the cloacal membrane. After the cloacal septum separates the hindgut from the urogenital sinus, the fused caudal ends of the müllerian ducts form the müllerian tubercle as they come in contact with the posterior aspect of the sinus. Persistence of the urogenital sinus can be associated with anorectal anomalies. Two different situations can arise. In the first situation, agenesis of Rathke plicae and failure of the müllerian ducts to migrate to the vestibule result in a persistent cloaca with a possibly septated vagina. In the second situation, defective caudal migration of the müllerian ducts or failure of the distal sinus to evert gives rise to persistence of the urogenital sinus after urorectal septation has occurred. Clinically, persistent urogenital sinus in females is classified into the following 3 categories:
Simple urogenital sinus is defined as a common channel into which genital and urinary tracts both open. Depending on timing of the arrest of vaginal differentiation, various degrees of anomaly can be identified. A long urogenital sinus with a short vagina and a high urethral opening characterize an early-stage defect. Later-stage anomalies are characterized by a short urogenital sinus with an almost normal vagina and low urethral orifice. The most severe degree of urogenital sinus persistence often is associated with anterior displacement of the anus, suggesting that a urorectal septum anomaly also is involved. The most important points in patient evaluation are definition of the exact anatomical picture, investigation of other anomalies (especially of the genital and urinary tracts), and identification of the mechanism of incontinence, if present. A genitogram, with retrograde injection of contrast material, is useful to delineate the anatomical aspects of the sinus and to clarify the relationship between the vagina and urethra. Voiding cystourethrography, urodynamic studies, and endoscopy are essential. Ultrasonography of the upper urinary system and pelvis can help screen for associated anomalies and define internal genital anatomy. Anatomy dictates treatment. If the urogenital sinus is low, simple U-flap vaginoplasty is effective in correcting the anomaly. If the vaginal entry into the urogenital sinus is high, more challenging surgery is needed. In fact, a division of the vaginal moiety with an associated pull-through vaginoplasty is needed. Moreover, relocation of the anus, if displaced anteriorly, may be necessary. Persistent urogenital sinus may be associated with an anorectal anomaly called persistent cloaca. Girls with persistent cloaca have the typical appearance of a closed perineum with a single orifice located behind the clitoris and no anus or vagina. If the convergence of bladder, vagina, and colon is low, the appearance may be of a relatively normal female perineum with imperforate anus. In such patients, obstruction of the urinary system is uncommon, because it opens, like the vagina and rectum, into a wide funnel-shaped urogenital sinus that drains freely. However, when the 3 organ systems converge at a higher level, the urogenital sinus is long. Frequently, the skin folds around the clitoris are so prominent that the structure has the appearance of a penis, thus inducing an erroneous gender assignment. In these cases, obstruction of the urinary tract is common. Treatment of the various forms of persistent cloaca is one of the most challenging problems of reconstructive surgery in pediatrics. Once the anatomy has been clearly defined, surgery may be performed. Most surgeons perform a colostomy to relieve colon obstruction. Distension of the bladder and vagina, which often obstructs both ureters, may be relieved by intermittent catheterization, thus avoiding the necessity of vesicostomy or vaginostomy. Complete definitive reconstruction for cloacal persistence should be deferred until the child is older than 1 year. When the sinus is shorter than 3 cm, the rectum is mobilized and detached from the vagina. The sinus should not be opened but should be mobilized and brought down intact. The common channel is divided and the separated openings of the urethra and vagina are placed in their normal positions. When the common channel of the cloaca is longer than 3 cm, the posterior approach to correction is preferred. Hendren has emphasized the necessity of correcting both urinary and rectal defects simultaneously.11, 12 Patient education MULTIMEDIA
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